Method for reaming an intramedullary canal

ABSTRACT

A method and apparatus useful in the reduction of a bone fracture is disclosed and relates to a guide rod inserted into a medullary canal of a bone. The guide rod includes a retention mechanism that holds the guide rod in place during the bone reduction procedure. The retention mechanism may include a finger member that contacts material within the bone to hold the guide rod in place.

This is a divisional of application Ser. No. 08/125,690 filed on Sep.24, 1993, now U.S. Pat. No. 5,509,919.

FIELD OF THE INVENTION

The present invention generally relates to a method and apparatus forreducing the fracture of a bone and particularly to a method andapparatus for holding a guide rod in place in a medullary canal of abone during reduction of a fracture in that bone.

BACKGROUND OF THE INVENTION

Prior to setting a bone fracture, the fracture must be reduced. That is,the various bone fragments or pieces must be repositioned in theirproper relative arrangement before the fractured bone can be fixed orstabilized for healing.

Various techniques exist for reducing bone fractures, one of which isdisclosed in U.S. Pat. No. 5,122,146. In that patent, the fracture isreduced using, in part, a fracture reduction tool and a "guide wire".Through manipulation of the fracture reduction tool (and the help of anassistant if necessary), proper alignment of the fragments is achieved.The proper alignment is then maintained by the insertion of the guidewire through the medullary canal of each fragment.

Further reduction and preparation for stabilization is performed byreaming the medullary canal of the fragments that are now held inalignment. This operation is achieved by sequentially advancing andretracting a series of hollow reaming instruments over the guide rod.With the use of each successive reaming instrument, the medullary canalis increased in size until it is enlarged sufficiently to receive a nailor pin that will permanently keep the bone fragments in proper alignmentand thereby stabilize the bone for healing.

Although not mentioned in U.S. Pat. No. 5,122,146, in practice, the useof a guide wire in the reduction of fractures can prove highlydisruptive. Most frequently this occurs during the reaming operationwhere the reaming instruments are being advanced and retracted over theguide wire.

Since the guide wire is not secured in position within the medullarycanal during the reaming operation, retraction of the hollow reaminginstrument, through contact with the guide wire, often pulls the guidewire out of position, even when the surgeon is using extreme caution.When this occurs, the entire reduction procedure must be started againthus obviously leading to greater risk of damaging the fractured area aswell as increasing the time required to complete the procedure.

No guide wires of the known prior art have provided any acceptablesolution to this problem. The guide wire of U.S. Pat. No. 5,122,146includes a bead-tip at its distal end, however the function of thebead-tip is primarily to prevent the reaming instrument from beingadvanced too far within the medullary canal; it does not secure theguide wire within the canal.

It is therefore the goal of the present invention to overcome theproblems associated with the use of a guide wire, guide rod or the likein the procedure of reducing fractures. Particularly, it is the goal ofthe present invention to provide a method and apparatus capable ofensuring that a guide wire (or guide rod or the like) is secured in adesired position in the medullary canal of the fractured bone throughoutthe reduction procedure.

The various novel features of the invention which are believed toachieve these goals as well as to provide other advantages andimprovements will be understood from the following specification andaccompanying drawings in which a preferred embodiment of the inventionis illustrated by way of example. It is expressly understood, however,that the specification and drawings are for purposes of description andillustration only and are not intended as a definition of the limits ofthe invention as set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a guide rod in accordance with an embodiment ofthe present invention;

FIGS. 2A-2B illustrate a second embodiment of a guide rod in accordancewith the present invention;

FIGS. 3A-3B illustrate a third embodiment of a guide rod in accordancewith the present invention;

FIGS. 4A-4B illustrate a fourth embodiment of a guide rod in accordancewith the present invention;

FIGS. 5A-5B illustrate a fifth embodiment of a guide rod in accordancewith the present invention;

FIGS. 6A-6C illustrate a sixth embodiment of a guide rod in accordancewith the present invention;

FIGS. 7A-7B illustrate a seventh embodiment of a guide rod in accordancewith the present invention;

FIG. 8 illustrates the positioning of a guide rod in accordance with anembodiment of the present invention within the medullary canal of afractured femur;

FIG. 9 illustrates the secured position of a guide rod in accordancewith an embodiment of the present invention within the medullary canalof a fractured femur;

FIG. 10 illustrates the advancement of a reaming instrument guided by aguide rod in accordance with an embodiment of the present invention;

FIG. 11 illustrates the secured position of a guide rod in accordancewith an embodiment of the present invention after retraction of thereaming instrument of FIG. 4;

FIG. 12 illustrates the insertion of a permanent nail over a guide rodin accordance with an embodiment of the present invention and theconfiguration of the guide rod just prior to removal of the guide rodfrom the medullary canal of a fractured femur.

DETAILED DESCRIPTION

A guide rod 100 in accordance with the present invention is depicted inFIG. 1 and includes an elongated rod section 101 which is substantiallycircular in cross-section. The rod section 101 may be made of a flexiblematerial so that the guide rod 100 may be used in reducing fracturesthat are either substantially straight or that have a degree ofcurvature. Provided at regular intervals along the length of theelongated rod section are radiopaque measuring markers 105 that areuseful for monitoring the location of the rod within the medullarycanal. Finally, the distal end 113 of the elongated rod section 101 isformed to have a bullet shape. This shape provides advantages over othershapes such as beaded ends or blunt shapes as it facilitates advancementof the guide rod 100 through the material within the medullary canal ofthe bone.

At the proximal end of the guide rod 100 is a handle arrangement 102that is gripped by the user and used to facilitate insertion of theguide rod into the medullary canal of a bone. Once the guide rod 100 isin place, the handle arrangement may be removed in order to allowfurther steps in the fracture reducing procedure.

At the distal end of the guide rod 100 is a guide rod retention device103 for retaining the guide rod 100 in place once it has been moved intoa desired position within the medullary canal of the bone. The retentiondevice includes a plurality of finger members 104 that are selectivelyactuatable between a first position where each finger member 104 restssubstantially within the cross-sectional profile of the guide rod 100(not shown) and a second position where each finger member 104 extendsflares outwardly from the cross-sectional profile of the guide rod 100.When in the second position, the finger members 104 come into contactwith material within the bone and thereby anchor the guide rod in thedesired position within the medullary canal.

It will be appreciated that any number of mechanisms may be incorporatedinto the guide rod 100 to provide the actuating function for the fingermembers 104. In one embodiment, that mechanism may include a screw-typedevice similar to that used in a rotary actuated ballpoint pen. Byturning the handle assembly 102, the finger members 104 emerge from thedistal end and spread outwardly to contact material within the bone.Other contemplated embodiments might use a tension notch device similarto that of a floor jack or a pressurized trigger device similar to thatused to actuate a balloon-tip catheter.

Instead of being actuated through the distal end of the guide rod 100 asdepicted in FIG. 1, it is contemplated the finger members 104 may beactuated outwardly from the cross-sectional profile of the guide rod 100as depicted in FIGS. 2-7. Finger members 104 actuated in this manner mayinitially rest completely within the cross-sectional profile or may restadjacent to the cross-sectional profile. A number of different ways maybe implemented to actuate the finger members 104 in this manner.

Referring to FIGS. 2A and 2B, the finger members 104 extend between thedistal end 113 of the guide rod 101 and a threaded nut member 201 thatis mounted on corresponding threads 200 on the guide rod. By rotatingthe nut member 201 through the handle assembly 102, the finger members104 begin bulging outwardly from the cross-sectional profile of theguide rod 100 as seen in FIG. 2B so as to come into contact withmaterial within the bone.

Referring to FIGS. 3A and 3B, the finger members 104 extend between thedistal end 113 of the guide rod 100 and a sealing ring 301 such as anO-ring that is mounted on an actuating shaft 300 that extends throughthe guide rod 100 and is attached to the distal end 113. By urging theactuating shaft 300 upwardly through the guide rod 100, the fingermembers 104 begin bulging outwardly from the cross-sectional profile ofthe guide rod 100 as seen in FIG. 3B so as to come into contact withmaterial within the bone. It is contemplated that the shaft 300 could belocked in place using a locking mechanism similar to that used in apush-button ballpoint pen or to that used in an umbrella.

Referring to FIGS. 4A and 4B, the finger members 104 extend between thedistal end 113 of the guide rod 100 and a ring 402 that is slidablymounted on the guide rod 100. Mounted on the guide rod 100 between thering 402 and the distal end 113 is a bladder 400 that is inflatablethrough air holes 401 located in the guide rod 100. Upon inflation ofthe bladder 400, the finger members 104 begin bulging outwardly from thecross-sectional profile of the guide rod 100 as seen in FIG. 4B so as tocome into contact with the material within the bone.

Referring to FIGS. 5A and 5B, the finger members 104 extend between thedistal end 113 of the guide rod and the end elongated shaft 101 of theguide rod 100. An actuating wire 500 extends through the shaft 101 andis connected to the distal end 113 of the guide rod 100. By urging thewire 500 upwardly through the guide rod 100, the finger members 104begin bulging outwardly from the cross-sectional profile of the guiderod 100 as seen in FIG. 5B so as to come into contact with the materialwithin the bone.

Referring to FIGS. 6A and 6B, a finger member 104 is pivotally attachedto the distal end 113 of the guide rod 100. A threaded nut 601 ismounted on the guide rod 100 through corresponding threads 600 on theguide rod 100. As the nut 601 is threaded downwardly towards the distalend of the guide rod 100, the body of the nut 601 forces the fingermember 104 to pivot such that a pointed end of the finger member 104 isurged outwardly from the cross-sectional profile of the guide rod 100 asseen in FIG. 6B so as to come into contact with the material within thebone. Of course, a plurality of finger members 104 may be utilized asdepicted in FIG. 6C.

Referring to FIGS. 7A and 7B, the finger members 104 extend between thedistal end 113 of the guide rod 100 and the end of the elongated rod 101of the guide rod 100. The inside of the elongated rod 101 serves as ahydraulic cylinder housing 701 for a hydraulic piston arrangement 700that is connected to the distal end 113 of the guide rod 100. Byintroducing and withdrawing fluid into and out of the cylinder housing701, the finger members 104 are actuated. When fluid is withdrawn, thedistal end 113 of the guide rod 100 is urged upwardly and the fingermembers 104 are urged outwardly from the cross-sectional profile of theguide rod 100 as seen in FIG. 7B so as to come into contact with thematerial within the bone.

Referring now to FIGS. 8-12, the use of the guide rod 100 in thereduction of a fractured femur is described. Initially, of course, thepatient has been anesthetized and an incision has been made to allowinsertion of various tools into the fractured area.

As shown in FIG. 8, the guide rod 100 is introduced into the medullarycanal 106 of the fractured bone and advanced towards the joint 107 ofthe bone. During this insertion and advancement step of the reductionprocedure, the finger members 104 of the retention mechanism 103 arekept within the circular cross-sectional profile of the guide rod 100,that is, the retention mechanism 103 is unactuated.

Once the guide rod 100 is located in the desired position, the retentionmechanism 103 is actuated by turning the handle assembly 102. This leadsto the flaring finger members 104, extending outwardly from thecross-sectional profile of the guide rod section 101 and contactingmaterial within the joint area 107 of the fractured bone and therebyanchoring the guide rod 100 into place as shown in FIG. 9.

The guide rod 100 thus being anchored into place, the surgeon may thenbegin the reaming stage of the procedure to prepare the medullary canal106 for receiving a permanent nail or rod 109 that will stabilize thefracture for healing. The finger members 104 are locked into place andthe handle arrangement 102 is then removed. A series of hollow reaminginstruments 108 are then sequentially advanced and retracted along theguide rod 100, the guide rod 100 having a diameter that is insertableinto the hollow of each reaming instrument 108. FIG. 10 illustrates thereaming operation.

Typically, there is little clearance between the guide rod 100 and thehollow of the reaming instrument 108, hence, advancement and retractionof the reaming instrument will often exert a force on the guide rod 100due to contact of the inside surface of the hollow reaming rod 108 withthe guide rod 100. However, since the finger members 104 of theretention mechanism 103 have anchored the guide rod 100 into place, suchcontact can be overcome without adversely effecting the guide rod'splacement; the guide rod will remain in its desired location throughoutthe reaming operation as seen in FIG. 11.

Once reaming has been completed, the medullary canal 106 is ready toreceive the permanent nail 109 that will stabilize the fracture asdepicted in FIG. 12. As with the reaming instruments, the nail 109 ishollow and therefore able to be guided into place by advancement overthe guide rod 100 with a known mallet and nail alignment assembly 110.During insertion, the guide rod is prevented from any movement urged bycontact between the nail 109 and the guide rod 100 because the guide rodis anchored into place by the finger members 104 of the retentionmechanism.

Once the nail 109 has been advanced to its desired final position, themallet and nail alignment assembly 110 is removed and the handleassembly 102 is remounted onto the guide rod 100. The retentionmechanism 103 is unlocked and deactuated thus causing the flaring fingermembers 104 to return to their original position within the elongatedrod section 101, out of contact with the material within the bone asdepicted in FIG. 12. This, of course, also releases the guide rod 100from its anchored position within the medullary canal 106. The guide rodis then removed from the medullary canal 106 leaving the nail 109 inplace. Finally, the nail is secured to the bone with a known drillingand nailing procedure.

While the invention has been described with reference to a particularembodiment, it is understood that the embodiment is merely illustrativeas there are numerous variations and modifications which may be made tothose skilled in the art. Thus, the invention is to be construed asbeing limited only by the spirit and scope of the appended claims.

What is claimed is:
 1. A method of using a guide rod in a medullary canal of a bone during reduction of a bone fracture, said guide rod having a retention mechanism for holding said guide rod in a desired position in said medullary canal, said method comprising the steps of:introducing said guide rod into said medullary canal of said bone; moving said guide rod into a desired position within said medullary canal; holding said guide rod in said desired position by moving at least one member of said retention mechanism into contact with material in said bone; advancing and retracting a series of hollow reaming instruments over said guide rod in order to enlarge said medullary canal.
 2. A method of using a guide rod as set forth in claim 1, wherein said at least one member of said retention mechanism is a finger member that is moved outwardly from a cross-sectional profile of said guide rod into contact with said material in said bone.
 3. A method of using a guide rod as set forth in claim 1, wherein said at least one finger member is moved outwardly from a substantially circular cross-sectional profile of said guide rod.
 4. A method of using a guide rod as set forth in claim 1, further including the step of advancing a permanent nail over said guide rod into a desired position within said medullary canal.
 5. A method of using a guide rod as set forth in claim 4, wherein said guide rod is released from being held in said desired position by moving said at least one member out of contact with said material in said bone and withdrawing the guide rod from said medullary canal through said permanent nail. 